Unsmellable Snake Camouflages Its Scent

If your favorite activity is lying motionless on the ground, you’d better make sure hungry animals can’t find you. Snakes and other creatures that hunt by ambush, waiting for their prey to wander past, often have impressive visual camouflage. But at least one type of viper seems to disguise itself in another way, too: its smell is undetectable to predators.

Puff adders (Bitis arietans) are big, fat vipers that move around very little while they wait for prey. They’re widespread in Af